Chapter 8 Notes – Photosynthesis

[Pages:6]Name: ____________________________________ !

Date: _______________________

Chapter 8 Notes ? Photosynthesis

Section 8-2 & 8-3 Photosynthesis: An Overview (p. 204-214) The study of energy capture and use begins with ___________________________.

? Photosynthesis is the process in which plants use the energy of __________________ to convert _______________ and carbon dioxide into ____________________ and high-energy carbohydrates (sugars and starches).

! ! ! ! ! ! ! ! ! ! What is the overall equation for photosynthesis?

The equation for photosynthesis is:

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carbon dioxide + water light sugar + oxygen

Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into oxygen and high-energy sugars.

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Where do plants get each material needed for photosynthesis? ? Carbon dioxide ? from the air that mammals __________________ out (through stomata--tiny _________________ on the leaf) ? Water ? from the ground through its ____________ system (xylem) ? Sunlight ? from the ___________ ? Chlorophyll ? made in __________________________

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Where do the products of photosynthesis go?

? Oxygen ? leaves the plant cells (through stomata) and goes into the ______________; some oxygen also remains _________________ plant cells.

? Glucose ? remains inside the __________________; used to make more complex carbohydrates, such as ___________________.

What is the role of light and chlorophyll in photosynthesis?

Light and Pigments

How do plants capture the energy of sunlight?

In addition to water and carbon dioxide, photosynthesis requires ________________ and ____________________________.

Energy from the sun travels to Earth in the form of _________________. Sunlight, which your eyes perceive as __________________ light, is actually a mixture of different ___________________________ of light. Many of these wavelengths, which are visible to your eyes as different ________________, make up the visible ____________________.

V

IB

GY

O

R

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Plants gather the sun's energy with light-absorbing molecules called _______________________.

? The main pigment in plants is __________________________. o There are two types of chlorophyll: chlorophyll _________ chlorophyll _________

? Chlorophyll absorbs light well in the ___________________________ and ______________ regions of the visible spectrum.

? Chlorophyll does not absorb light well in the ___________________ region of the spectrum. Green light is ______________________ by leaves, which is why plants look green. o Plants also contain red, orange, and yellow pigments, called ____________________________, that absorb light in other regions of the spectrum.

Light is a form of ____________________, so any compound that absorbs _______________ also absorbs energy from light.

? When chlorophyll absorbs light, much of the energy is transferred directly to _____________________ in the chlorophyll molecule, raising the energy levels of these electrons. o These high-energy electrons are what make photosynthesis work.

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Inside a Chloroplast In plants, photosynthesis takes place inside ___________________________.

? Chloroplasts contain ________________________ --saclike photosynthetic membranes.

? Thylakoids are arranged in stacks known as _______________. A singular stack is called a ______________________.

? The region outside the thylakoid membranes is called the ____________________.

Stroma

Single thylakoid

Granum

Overview of Photosynthesis The process of photosynthesis occurs in two stages:

1. The _____________________________________ reactions ? takes place within the _______________________ membranes.

2. The __________________ ________________ - takes place in the _________________.

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The two sets of photosynthetic reactions work together: ? The light-dependent reactions trap _______________ energy in ____________________ form. ? The Calvin cycle uses that chemical energy to produce high-energy _________________ from carbon dioxide and water.

Electron Carriers Remember how we said that when light strikes a chlorophyll molecule, it excites _______________________?

? Cells need a way to transport these high-energy electrons from ________________________ to other molecules.

? Cells use electron ______________________ to transport these electrons. An electron carrier involved in photosynthesis is called __________________.

? NADP+ transports electrons to different parts of the ________________________. o NADP+ accepts and holds __________ high-energy electrons (e-) along with a ______________________ ion (H+). This converts the NADP+ into NADPH.

NADP+ + 2e- + H+ !

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NADPH

Light-Dependent Reactions What happens in the light-dependent reactions? In the presence of ______________, the light-dependent reactions produce ___________________ gas and convert ADP and NADP+ into the energy carriers ___________ and ___________________.

Summary of the light-dependent reactions:

Uses

Produces

ADP

ATP

NADP+

NADPH

H2O

O2

Sunlight

The Calvin Cycle What is the Calvin cycle? The Calvin cycle uses _______________ and _________________ from the lightdependent reactions to produce high-energy _________________.

? Because the Calvin cycle does not require light, these reactions are also called the light __________________________ reactions.

Summary of the Calvin cycle:

Uses

Produces

ATP

ADP

NADPH

NADP+

CO2

C6H12O6

Factors Affecting Photosynthesis Many factors affect the rate of photosynthesis, including: _________________, __________________________, and intensity of ___________________.

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